Radeon HD 7770 vs Radeon R9 M265X

Intro

Compare that to the Radeon R9 M265X, which has a GPU core clock speed of 575 MHz, and 2048 MB of GDDR5 RAM running at 1125 MHz through a 128-bit bus. It also is made up of 640 Stream Processors, 40 TAUs, and 16 ROPs.

Display Graphs

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Power Usage and Theoretical Benchmarks

Memory Bandwidth

Both cards have exactly the same memory bandwidth, so in theory they should have identical performance. (explain)

Texel Rate

The Radeon HD 7770 will be much (about 74%) better at AF than the Radeon R9 M265X. (explain)

Radeon HD 7770		40000 Mtexels/sec
Radeon R9 M265X		23000 Mtexels/sec
	Difference: 17000 (74%)

Pixel Rate

If running with high levels of AA is important to you, then the Radeon HD 7770 is superior to the Radeon R9 M265X, and very much so. (explain)

Radeon HD 7770		16000 Mpixels/sec
Radeon R9 M265X		9200 Mpixels/sec
	Difference: 6800 (74%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the largest amount of information (measured in megabytes per second) that can be moved past the external memory interface within a second. It is calculated by multiplying the bus width by its memory clock speed. In the case of DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This number is worked out by multiplying the total texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.

Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.